• Journal of the Society of Naval Architects of Korea
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• v.42 no.2 s.140
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• pp.98-104
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• 2005

The mathematical models of hydrodynamic force and moment acting on a ship at low speed range should be established differently from the ones at nominal cruising speed range since a ship moves with large drift angle or rotates in a stationary position. We modified widely used Yoshimura's cross flow model in order to apply the system identification method to estimate parameters in the model. The apparatus and the procedure of free running model test were suggested so that the parameters in the model be estimated. The validity of our proposing modified model and test procedure was confirmed by comparison with the results of simulated model test.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.243-248
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• 2020

In addition to a range of H&S documentation, a range of actions, beliefs, interventions, practices, and states are important in terms of achieving optimum construction H&S. Conclusions include that H&S documentation facilitates and assists planning, organising, leading, controlling, and coordinating H&S. Furthermore, current H&S documentation: is inappropriate in that it can be complex, generic, lengthy, onerous, repetitive (duplicative), and vague; engenders dubious practices; generally, 'does not add the potential value'; shifts the focus from the physical process, and could be improved. Recommendations include: industry associations should review their 'audit system' to interrogate the allocation of points; H&S documents must reflect the intention of the requirement; the synergy between H&S documentation, and actions, interventions, and practices should be investigated, digested, and focused upon, and 'audits', or rather inspections, should focus more on the physical process, actions, interventions, and practices, than documentation.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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• pp.29-35
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• 2018

This paper presents a quantitative evaluation method and result of moving vehicle perception using automotive radar. It is also important to analyze the accuracy of the perception algorithm quantitatively as well as to accurately percept nearby moving vehicles for safe and efficient autonomous driving. In this study, accuracy of the automotive radar-based perception algorithm which is developed based on interacting multiple model (IMM) has been verified via vehicle tests on real roads. In order to obtain experimental data for quantitative evaluation, Long Range Radar (LRR) has been mounted on the front of the ego vehicle and Short Range Radar (SRR) has been mounted on the rear side of both sides. RT-range has been installed on the ego vehicle and the target vehicle to simultaneously collect reference data on the states of the two vehicles. The experimental data is acquired in various relative positions and velocity, and the accuracy of the algorithm has been analyzed according to relative position and velocity. Quantitative analysis is conducted on relative position, relative heading angle, absolute velocity, and yaw rate of each vehicle.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.325-331
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• 2018

This paper deals with the dynamical analysis of a vessel that leads to capsize in regular beam seas. The complete investigation of nonlinear behaviors includes sub-harmonic motion, bifurcation, and chaos under variations of control parameters. The vessel rolling motions can exhibit various undesirable nonlinear phenomena. We have employed a linear-plus-cubic type damping term (LPCD) in a nonlinear rolling equation. Using the fourth order Runge-Kutta algorithm with the phase portraits, various dynamical behaviors (limit cycles, bifurcations, and chaos) are presented in beam seas. On increasing the value of control parameter ${\Omega}$, chaotic behavior interspersed with intermittent periodic windows are clearly observed in the numerical simulations. The chaotic region is widely spread according to system parameter ${\Omega}$ in the range of 0.1 to 0.9. When the value of the control parameter is increased beyond the chaotic region, periodic solutions are dominant in the range of frequency ratio ${\Omega}=1.01{\sim}1.6$. In addition, one more important feature is that different types of stable harmonic motions such as periodicity of 2T, 3T, 4T and 5T exist in the range of ${\Omega}=0.34{\sim}0.83$.

• Journal of Food Hygiene and Safety
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• v.2 no.1
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• pp.3-8
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• 1987

ABSTRACT-Agricultural products collected from the suburbs of Chuncheon in 1984 were analyzed for carbamate pesticides by GLC-NPD. O-tert-butyl phenyl methyl carbamate(BPMC) was detected in most samples and their residue levels in strawberry, tomato, cucumber, grape, apple and chinese cabbage were in the range of non-detectable to 0.2356 ppm(Av. 0.0539 ppm). 1- naphthyl methyl carbamate(N AC) were detected in cucumber, grape and chinese cabbage and their residue levels were in the range of non-detectable to 0.0265 ppm. O-cumeryl methyl carbamate(MIPC) was detected in only chinese cabbage and its residue levels were in the range of non-detectable to 0.0059 ppm. Detection frequencies of BPMC, MIPC and NAC in the chinese cabbage were higher than those the others.others.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.352-356
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• 2016

Objective : The efficacy and safety of manual aspiration thrombectomy using Penumbra in an acute occlusion of large intracranial arteries has been proven in many previous studies. Our study aimed to retrospectively assess the efficacy and safety of manual aspiration thrombectomy using Penumbra in patients with small vessel occlusions (M2 segment of the MCA). Methods : We conducted a retrospective review of 32 patients who underwent manual aspiration thrombectomy using the Penumbra 4 MAX Reperfusion Catheter for treatment of an M2 occlusion between January 2013 and November 2014. We evaluated immediate angiographic results and clinical outcomes through review of patient electronic medical records. Results : There were slightly more men in this study (M : F=18 : 14) and the median age was 72.5 (age range : 41-90). The rate of successful recanalization (TICI grade ${\geq}2b$) was 84% (27/32). NIHSS at discharge and favorable clinical outcomes at 3 months were significantly improved than baseline. Median initial NIHSS score was 10 (range : 4-25) and was 4 (range : 0-14) at discharge. Favorable clinical outcomes (mRS score ${\leq}2$ at 3 months) were seen in 25 out of 32 patients (78%). There were no procedure-related symptomatic intracerebral hemorrhages. One patient expired after discharge due to a cardiac problem. Conclusion : Manual aspiration thrombectomy might be safe and is capable of achieving a high rate of successful recanalization and favorable clinical outcomes in patients with distal cerebral vessel occlusion (M2).

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.81-88
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• 1996

In order to investigate the electrical properties of transformer oils for large power, the characteristics of AC and Impulse breakdown in gap length of 1.0~2.5mm and that of volume resistivity were researched in temperature range of 20~$100^{\circ}C$. An geometrical capacitance of electrode with coaxial cylindrical shape for measuring the volume resistivity was 16pF, and highmegohm meter with model no. VMG-1000 was used, and also the applied voltage were DC 100, 250 and 500V. In the dependance of breakdown characteristics due to electrode gap length, it was confirmed that breakdown voltage was nearly uniform by volume effect according to the increase of gap. In the characteristics for AC breakdown, the dielectric strength was increased to $90^{\circ}C$ but decreased over $90^{\circ}C$, and also in case of impulse breakdown, it was increased to 7$0^{\circ}C$ and at dated $70^{\circ}C$ over in temperature range. The calculated mobility of oils in the characteristics for impulse breakdown were about $10^{-5}$~$10^{-4}cm^2/V{\cdot}S$, and the value of volume resistivity was almost invariable in low temperature range, regardless of voltage by the stable thermal properties, and it indicated a peak at $50^{\circ}C$ and had a sudden change to decrease over that temperature, and also the value of volume resistivity in 250V/mm at $80^{\circ}C$ is suitable for the International electrical standards, it was confirmed.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.117-126
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• 2012

Understanding driver's characteristic of visual activity is important process because driver depends on a visual signal more than 90% for getting outside information needed to drive, thus a series of driving, including perception, judgement, and activity, is completed. This study analyzes quantified driver's sight range in curved section where recognition of various information is critical due to biggest speed change among sections. Simulation is utilized for this study because of safety problem on field experiment and difficulties in using equipment. Building 6 roads that have different in curve radius by virtual driving map, experiment is carried out recruiting 30 people. Through analytical researches, it shows that drivers keep an eye on direction of driving, and driver's visual range is narrowed on left curve than right curve, and the more curve radius become small, the more drivers see in narrow angle.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.506-509
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• 2014

This study was conducted to identify transition characteristics of mercury in several selected medicinal plants and to find the appropriate management for production of safety food. Cultivated soils and medicinal plants were collected at 29 sites for Angelica gigas (Korean angelica root), 68 sites for Platycodon grandiflorum (Balloon flower), 35 sites for codonopsis lanceolata (Deoduck), 36 sites for Dioscorea batatas (Chinese yam), 32 sites for Rehmannia glutinosa (Foxglove), 16 sites for Cnidium officinale makino (cnidium), and 26 sites for Astragalus membranaceus (milk vetch root) during the harvest season of 2013. Mercury in the soils and medicinal roots were analyzed with a Direct Mercury Analyzer. Average content of mercury in soils cultivated medicinal plants was $0.023mg\;kg^{-1}$ (range: from 0.003 to $0.074mg\;kg^{-1}$) and average content of mercury in medicinal plants was $0.003mg\;kg^{-1}$ (range: from 0.001 to $0.011mg\;kg^{-1}$), indicating that mercury in the surveyed soils and medicinal plants were not exceeded the Korean regulation.

• Mass Spectrometry Letters
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• v.4 no.1
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• pp.18-20
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• 2013

Headspace solid phase micro-extraction gas chromatography/flame ionization detection (HS-SPME-GC/FID) method was compared with headspace gas chromatography/mass selective detection (HS-GC/MS). Organic solvent-spiked urine as well as urine samples from workspace was analyzed under optimal condition of each method. Detection limit of each compound by HS-SPME-GC/FID was $3.4-9.5{\mu}g/L$, which enabled trace analysis of organic solvents in urine. Linear range of each organic solvent was $10-400{\mu}g/L$, with fair correlation coefficient between 0.992 and 0.999. The detection sensitivity was 4 times better than HS-GC/MS in selected ion monitoring (SIM) mode. Accuracy and precision was confirmed using commercial reference material, with accuracy around 90% and precision less than 4.6% of coefficient of variance. Among 48 urine samples from workplace, toluene was detected from 45 samples in the range of $20-324{\mu}g/L$, but no other solvents were found. As a method for trace analysis, SPME HS GC/FID showed high sensitivity for biological monitoring of organic solvent in urine.